However, ever since floor general Rajon Rondo was lost for the season, the Celtics have sought another leader, which has forced Bradley, in his third season in green, to move from shooting guard to point guard and to a leadership role faster than he expected.

A key part of that role is to be vocal, and on a team on which he’s the youngest starter (22) among veterans such as Kevin Garnett (36) and Paul Pierce (35), Bradley isn’t one to talk — at least not yet. He’d rather lead by example than tell others what to do.

“I don’t feel like I’ve earned that right,” he said before practice Tuesday.

That their point guard is soft spoken is OK among the Celtics, in part because, as assistant coach Armond Hill said of Bradley, “His defense speaks loud.”

Indeed. With a minumum of 200 defensive plays this season, Bradley is second in the league in allowing a mere 0.678 points per play, according to Synergy Sports data.

But the guard is working on becoming more vocal, a process that requires time.

“You have to be vocal — and not only that, but you have to be an extension of the coach,” he said. “They try to instill that in me now so that next year, I can be a leader on the court.”

His coaches are patient.

“That’s not anything I’m looking for right now,” coach Doc Rivers said. “I just want him to keep playing and play hard.

“He’s still a student of the game,” Garnett said. “You’ve got to remember that he’s still young, still learning.”

But, Garnett added, “He has to speak up. It’s a good learning tool for him, though. I feel like it’s only helping him in the long run.”

For now, Bradley’s defense is what speaks volumes, and he’s noticed its impact beyond numbers.

“It’s been different every single year as far as the respect level for me because they see how hard I work,” Bradley said. “It just takes time to gain trust and for me to be able to lead them.”

Among Bradley’s biggest admirers is Garnett, who not only called Bradley a “silent leader” who does it by example but said Bradley’s defense inspires a defense-minded group.

“Avery is everything to our defense,” Garnett said. “He’s the anchor, if you will. He’s the true inspiration of what it is.

“He’s up on the ball, like 95, 90 percent of the time. If you look at any other guard in the league, no one is playing defense like he is. He’s just tenacious, man.”

Is there no one else in the league who plays like Bradley?

“Not like that,” said Bulls coach Tom Thibodeau, a former Celtics assistant.

“And he’s been tough for a long time now.”

What sets Bradley apart, Thibodeau said, is “His energy. His energy and toughness.”

But if anyone expends the effort that Bradley does defensively, it’s Clippers guard Eric Bledsoe.

When asked who plays length-of-the-court defense in the NBA, Bledsoe could think of only two names: “There’s me – and Avery Bradley.”

Said Rivers: “There’s not a lot of guys that want to do it. There are probably a lot of guys that can do it. But there are very few that want to, and that’s the key part.

“Avery enjoys it, he enjoys the defensive assignments. He looks at the other team’s best player at the 1, 2, or even 3 at times, and he’s looking forward to matchups. That’s a guy who understands who he is, and that’s a good sign.”

It’s an exhausting enterprise — and, as Rivers pointed out, there is rarely a moment when Bradley isn’t out of breath. Bledsoe knows the feeling, one that he calls satisfying.

“At the end of the day, you don’t want to leave the game with any regrets,” he said. “You want to leave the game tired. You want to feel like you’ve done something, and you want the opponent to feel the same way.”

Warriors guard Stephen Curry faced Bradley in a much-anticipated matchup last week, and though Curry scored 25 points, each was hard-earned, and his team lost.

“You’re prepared for it,” Curry said of facing Bradley, “but when you’re in the game and trying to stay fresh and get the ball down the floor, he tries to take you out of your rhythm.”

Bradley missed the first 30 games of the season while rehabbing from surgery on both shoulders, and Garnett doesn’t believe Bradley is 100 percent healthy.

“Which is scary,” Garnett said.

Rivers said an official even asked about Bradley’s shoulders during the Golden State game.

“[The referee] said, ‘I had one shoulder done and I was out six months and I still feel bad.’ I said, ‘That’s why you’re an official,’ ” Rivers said with a laugh.

Given how Bradley has played point guard in Rondo’s absence, his stock has increased exponentially.

A Western Conference scout said that around the trade deadline, Bradley was considered one of the top three backup point guards in the league, along with Bledsoe and Golden State’s Jarrett Jack.

“He’s just so smart,” the scout said. “And he plays phenomenal defense.”

And for Bradley, that style of defense is his preferred style of leadership — actions, not words.

“You don’t want to follow anybody you don’t respect,” he said. “I feel like when my teammates see how I leave everything out on the floor, and give my all, it kind of makes them follow me.”

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